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post #1 of 7 Old 02-14-2015, 07:29 AM - Thread Starter
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Speaker cavity behind screen

I'm struggling with a design component for my new room. My intent has always been to place the LCR either behind the screen or GOM'd side cavities. Are there any recommendations or guidance out there for the construction of the cavities? Will placing the speaker in a confined space be detrimental to the sound?
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post #2 of 7 Old 02-14-2015, 07:53 AM
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Originally Posted by Gouie View Post
Will placing the speaker in a confined space be detrimental to the sound?
It will DRAMATICALLY alter the response characteristics of the speaker vs. the freespace characteristics which the speaker maker designed them in. Unless of course you are using inwalls. It's never a good idea to "mount" an already boxed speaker into a cavity (unless it was designed as such). Folks gotta do what they gotta do with the space and equipment they have, but that sort of arrangement will change the characteristics of the speaker a lot. Diffraction and bass are just a few.

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post #3 of 7 Old 02-14-2015, 08:15 AM - Thread Starter
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That's what I was thinking. I'm just beginning my theatre room journey and see so many out there that have no speakers visible. Would the assumption be that they are built ins or less concerned about the quality of the sound? I am 99% movie and am a firm believer that big video need big sound. To that end I guess I will have to change my thought and plan to have the speakers visible. I can't imagine that one can achieve that big sound with built ins.
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post #4 of 7 Old 02-14-2015, 08:31 AM
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Don't give up on your vision. There are many speakers suitable for Baffle walls that will do just fine in-wall. You just need to do your research and you may need to be prepared to apply some equalization to the final result (most theaters need equalization anyway). As for the cavities you can just apply all the principles of Backer boxes to building the bump out cavities. Search for threads discussing backer boxes. In my Rawlinsway project I stuck the butt end of the rear speakers in the wall to save space. some details of the backer boxes are shown in that thread.

I built 4Pi speakers for my theater and have them behind my AT screen which is mounted on a false fabric wall. They however do fine mounted in wall and have actually been used like that in a recording studio monitor setup.

http://audioroundtable.com/forum/ind...udio#msg_60905

just imagine hanging your screen in front of the that wall of speakers, the sound will be plenty big.

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post #5 of 7 Old 02-14-2015, 01:05 PM
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Quote:
Originally Posted by Gouie View Post
That's what I was thinking. I'm just beginning my theatre room journey and see so many out there that have no speakers visible. Would the assumption be that they are built ins or less concerned about the quality of the sound?
Screen walls don't have to be substantial, so the speakers don't need to be necessarily built in to boxes. On my screen wall, I used on wall speakers and have the screen mounted about 8 inches off the wall to hide them. Fabric covered rigid insulation panels make up the rest of the wall. Essentially the front wall of the theater has 2 four foot 2x4s strapped to the drywall.

If you have enough room and want large floor standing speakers you could still do a very light weight screen wall with fabric covered frames and a couple of 2x4s to hold your screen a few feet off the front wall.

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post #6 of 7 Old 02-14-2015, 07:10 PM
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I built a AT screen and placed a baffle wall behind it. Google THX Baffle wall. Anyway the speakers I am using behind the screen have 5 1/4 woofers. The baffle wall lowers the bass of the speakers so they can reproduce an octave lower than they would if they were sitting on a shelf. I have used Audessey XT32 to equalize the system and Audessey has the speakers crossed over at 60 hz. Not bad really. My IB subs bring up the bottom end quite nicely.

The trick is not to use speakers with a port on the back if you build a baffle wall. Ports in the front are fine. A lot of people will talk about how the whole system needs to be engineered to work right. Well, fine, but I like to experiment. It has worked out very well for me without hiring any audio engineers. I figured XT32 would do the work of the equalizing for me. I agree with Bigmouth. Don't give up your vision. I will add to that don't let people scare you out of what you want to do in YOUR theater room. If you don't like the results, start over.

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post #7 of 7 Old 02-16-2015, 06:07 AM - Thread Starter
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Speaker cavity behind screen

Thanks for the encouragement everyone. I have been envisioning this build for years and am now fortunate enough to be able to put the plan into action. I know one learns best by diving in I just don't want to make that one big mistake that I regret forever. Big, I have run through a couple of your documented builds and have to say you have inspired a number of concepts in my room. Better yet you have have my wife excited about the possibilities!

Regarding the pi speakers, I have an employee that dabbles in the recording business and has mentioned them before. I hadn't considered them in a theatre application. Obviously they would shine at 2.0 but how are you finding them in multi channel? I had started down the horn route but was convinced by a local reseller that they are generally too bright and hard to listen to for any length of time. Did you use them for your surrounds as well?
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